18400 has 36 divisors (see below), whose sum is σ = 46872. Its totient is φ = 7040.

The previous prime is 18397. The next prime is 18401. The reversal of 18400 is 481.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 789 + ... + 811.

It is an arithmetic number, because the mean of its divisors is an integer number (1302).

2¹⁸⁴⁰⁰ is an apocalyptic number.

18400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23436).

18400 is an abundant number, since it is smaller than the sum of its proper divisors (28472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18400 is a wasteful number, since it uses less digits than its factorization.

18400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 18400 is about 135.6465996625. The cubic root of 18400 is about 26.4001224359.

18400 divided by its product of nonzero digits (32) gives a palindrome (575).

Adding to 18400 its reverse (481), we get a palindrome (18881).

The spelling of 18400 in words is "eighteen thousand, four hundred".